Can't delete or rename files/directories

Hope someone can help me on this:

1) I can't seem to be able to rename any of my files or directories.

2) I can't delete some files too.

Both actions kept on prompting me the dialog box "550 error/Move failure". Neither the online uploader nor the FTP works for this.

:(

[admin]

You can't rename folders or files.

Just delete the file, upload again.

Deleting files will work fine.

If you have problem in deleting file, copy the full FTP message you get while deleting a file.

This is what I get for deleting and renaming files/directories.

"550 Rename/move failure".

This problem only occured when I wanted to delete one particular folder and one sub folder. I can't even move the files in those folders to another new directory.

Please help! :(